JEE Main 2019PhysicsCenter of Mass Momentum and CollisionMediumMCQ

JEE Main 2019 — Center of Mass Momentum and Collision Question with Solution

JEE Main 2019 (09 Jan Shift 1)

Question

Three blocks A, B and C are lying on a smooth horizontal surface, as shown in the figure. A and B have equal masses, m while C has mass M. Block A is given an initial speed v towards B due to which it collides with B perfectly inelastically. The combined mass collides with C, also perfectly inelastically . 56th of the initial kinetic energy is lost in the whole process. What is the value of M/m?

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Show full solutionCorrect option: B
Correct answer
B4

Step-by-step explanation



mv=m+mv′

m+mv′=m+m+Mvf

∴ final velocity vf=m2m+Mv

Initial energy =12mv2

Final energy  =122m+Mmv2m+M2

Given that 5612mv2=12mv2-122m+Mmv2m+M2

112mv2=12m2v22m+M

6m=2m+M

Mm=4

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About this question

This is a previous-year question from JEE Main 2019, covering the Center of Mass Momentum and Collision chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.